This invention relates to apparatus for automatically tying bales of material formed and compacted in a continuous extrusion type baling machine. Such baling machines are old and well known in the baling art and comprise conventionally a horizontal baling chamber having sides for constraining the bale laterally and an open end of controllable cross section from which the bales are extruded, and a feed hopper opening into the top side of the baling chamber for delivering material to be baled (for example, shredded paper). A baling head reciprocates in the baling chamber past the feed hopper opening between a rearward position of retraction and a forward position of extension. The baling head conventionally is driven by a hydraulic ram.
In operation, a charge of compressible material is dumped into the hopper and passes into the baling chamber when the baling head is retracted. Successive charges are compressed and compacted together in the baling chamber and against the resistance of the material previously compressed and being extruded through the throat by repeated strokes of the baling head. In this manner a length of compacted and compressed material is formed and extruded through and out the open end of the baling chamber. When a bale; i.e., length of compressed material suitable and convenient for handling, is accumulated in the baling chamber, the bale is bound and tied with a suitable number of wires, preferably while held in a compressed state between the immediately preceding and last bale to be tied and the baling head.
Bale ties, in the past, have been placed and twisted together or otherwise secured by hand operations. For example, U.S. Pat. No. 3,024,719 discloses, among other things, a horizontal, continuous baler equipped to place blocks between the otherwise abutting ends of successively formed bales. The blocks are provided with grooves on opposite faces and extending laterally across the ends of the bales. A tie wire can be passed through the grooves and along the sides and thus around the bale being tied. Conventionally, the ends of a tie are twisted together.
Such a method of and apparatus for tying bales is slow and expensive because of the labor required and the blocks used. There has been a long-standing need for automatic tying apparatus that would operate unattended and without blocks, and which could conveniently and economically be used as something of an accessory to a conventional horizontal continuous baler. Past attempts at providing such an automatic tying apparatus have only partially satisfied the need. Some of these attempts have been in connection with agricultural balers. The problems encountered there are not the same as in the industrial type baler application. For example, the forces applied to compress hay and the like are typically much less than those encountered in large industrial baling machines. Also, tying apparatus on agricultural balers must usually accommodate the necessity for trailering the equipment during operation. Such a hay baler with tier is described in U.S. Pat. No. 2,585,425.
Automatic tiers for industrial type balers have been proposed in the past. The apparatus described in U.S. Pat. No. 3,528,364 is typical of these. In conjunction with a generally conventional horizontal extrusion baler, material to be baled is compressed and accumulated in a baling chamber and against loops of tie wire which extend back along the sides of the bale being formed to wire supplying reels located on each side of the baler.
Extending laterally out from one side of the baler, generally at the forward most position of the baling head, a substantial auxiliary structure is provided for carrying a loop of the wire lying against the one side of a bale just completed across the baling chamber to the other side and to the wire lying therealong. The wire carrier or needle is extended through open sided slots in the face of the baling head while it is in its forward most position.
On the other side of the bale another auxiliary structure standing beside and extending out from the baler comprises means for twisting together the two adjacent parts of each wire passed around the bale and for cutting the twisted wires from the supply reels with a loop through the baling chamber remaining against which the next bale will be formed.
Such apparatus has serious shortcomings and disadvantages. For example, automatic wire tying apparatus of the type described above preempts a substantial amount of floor space over and above that required for the baler itself because of the structures which extend laterally out from both sides of the baling machine. A further disadvantage results from the opposite-side arrangement of the two parts of the tying apparatus in that a baler utilizing it cannot be located close to a wall as is typical of baler locations, since the tying apparatus on both sides of the baler must be provided floor space for itself and for servicing it.
Installation of the opposite-side type tier apparatus is complicated by the need for accurately aligning and relating the two spaced and separate parts to each other and to the baler if even modestly successful operation is to be achieved. Installation is expensive and time consuming involving floor supports on both sides of the baler, and the chances for operational failures due to misalignment are increased.
Another disadvantage of the opposite-side arrangement grows out of the substantial amount of loose material being baled that escapes from the machine during baling and lodges in and on the mechanism. The open sided slots in the baling head through which the needles and wire loops must be pushed from one side of the baling chamber to the other obviously become congested with loose material being baled as the baling head is pressed into each charge of material. Thus, in the opposite-side apparatus described above, each needle as it passes through its associated slot in the baling head carrying a loop of wire to the opposite side, must clear the groove ahead of it of the loose material packed therein and then discharge the material on the wire positioning, twisting and cutting mechanism. This debris tends to prevent the free and smooth operation of the tying and cutting mechanism.
A further disadvantage of past tying machines relates to the manner of joining the ties together and to the resistance of the joints to becoming undone. It will be noted that each completed tie placed around a bale by apparatus having a wire supply on both sides of the baler as described above, has two joints in it. One is near a front corner of the bale and joins the ends of the wires on each side of the bale to form a loop passing in front of the bale being formed. The other is near a rear corner of the bale and joins together the two wires passing around the bale. The joint at the after corner of one bale and at the forward corner of the succeeding bale are formed at the same time and severed by a cutter. It is common practice to twist the forward and after joints the same relative direction. Thus, the twisting action producing an after joint is in a direction which tends to untwist the previously twisted forward joint.